This invention relates in general to apparatus for sensing displacement or position of an object, and in particular to apparatus in which the displacement of the object is measured electrically as the object is moved relative to another element, with which the object maintains sliding (mechanical) contact.
In the operation of various mechanical and electro-mechanical systems, it is necessary to monitor the position and displacement of either some element of the system or some object which is not part of the system. For example, in robotic systems it is almost always necessary to monitor and control the movement and position of various component parts of the systems, such as an arm, fingers or other grasping elements, etc. Such monitoring and control yields the dexterity and precision required for a robotic system to carry out its functions.
Prior art mechanisms for sensing position and displacement have most often utilized a direct connection between the article or object whose position or displacement was to be monitored, and some type of gauge, needle or other visual indicator. Movement of the article or object would thus cause a corresponding movement of the gauge or needle. As expected, such mechanisms have typically been large and cumbersome, have lacked precision in carrying out the monitoring function, and have been unreliable.
Although electronic apparatus for measuring position and displacement has come into greater use in recent years and has at least partially solved the bulkiness and imprecision problems of the prior art mechanism, such apparatus has been complicated in design and thus difficult to manufacture and maintain.